Dictionary

A built-in data structure that holds key-value pairs.

Description

Dictionaries are associative containers that contain values referenced by unique keys. Dictionaries will preserve the insertion order when adding new entries. In other programming languages, this data structure is often referred to as a hash map or an associative array.

You can define a dictionary by placing a comma-separated list of key: value pairs inside curly braces {}.

Creating a dictionary:

var my_dict = {} # Creates an empty dictionary.

var dict_variable_key = "Another key name"
var dict_variable_value = "value2"
var another_dict = {
    "Some key name": "value1",
    dict_variable_key: dict_variable_value,
}

var points_dict = {"White": 50, "Yellow": 75, "Orange": 100}

# Alternative Lua-style syntax.
# Doesn't require quotes around keys, but only string constants can be used as key names.
# Additionally, key names must start with a letter or an underscore.
# Here, `some_key` is a string literal, not a variable!
another_dict = {
    some_key = 42,
}

You can access a dictionary's value by referencing its corresponding key. In the above example, points_dict["White"] will return 50. You can also write points_dict.White, which is equivalent. However, you'll have to use the bracket syntax if the key you're accessing the dictionary with isn't a fixed string (such as a number or variable).

@export_enum("White", "Yellow", "Orange") var my_color: String
var points_dict = {"White": 50, "Yellow": 75, "Orange": 100}
func _ready():
    # We can't use dot syntax here as `my_color` is a variable.
    var points = points_dict[my_color]

In the above code, points will be assigned the value that is paired with the appropriate color selected in my_color.

Dictionaries can contain more complex data:

var my_dict = {
    "First Array": [1, 2, 3, 4] # Assigns an Array to a String key.
}

To add a key to an existing dictionary, access it like an existing key and assign to it:

var points_dict = {"White": 50, "Yellow": 75, "Orange": 100}
points_dict["Blue"] = 150 # Add "Blue" as a key and assign 150 as its value.

Finally, dictionaries can contain different types of keys and values in the same dictionary: